Shortfield Tips
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Shortfield Tips
After watching this video http://www.pprune.org/forums/showthread.php?t=218678 it appears this poor guy got his mass and balance incorrect for a shortfield take off. This got me thinking... I'm only a low hour PPL with not a lot of experience outside of long, wide, paved runways. With the evenings getting longer and the weather finer, I hope to fly (and out) of some short and grass strips around the country this summer.
I think it would be helpful if some of the more experienced pilots on this forum could lend us some words of wisdom re shortfield operations.
Answers on the back of a postcard
I think it would be helpful if some of the more experienced pilots on this forum could lend us some words of wisdom re shortfield operations.
Answers on the back of a postcard
Spend serious time with AFM.
Know your density altitude
Pace out AFM ground roll on landing + safety factor from other end of runway and mark it -- if you're not in the air by that point, you have a reasonable chance to stop and reconsider without damage to a/c or people.
Work out distance to clear 50' obstacle and climb rate at density altitude to determine performance margins against terrain, especially if rising.
There is a takeoff performance computer available which can be used to take in account runway slope, weight and wind. Take with big grain of salt.
Remember that overruns are generally less likely to kill you than flying into something
Know your density altitude
Pace out AFM ground roll on landing + safety factor from other end of runway and mark it -- if you're not in the air by that point, you have a reasonable chance to stop and reconsider without damage to a/c or people.
Work out distance to clear 50' obstacle and climb rate at density altitude to determine performance margins against terrain, especially if rising.
There is a takeoff performance computer available which can be used to take in account runway slope, weight and wind. Take with big grain of salt.
Remember that overruns are generally less likely to kill you than flying into something
MGP
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Shortfield tips
Don't forget that your aircraft flight manual uses results of a new aircraft with a new engine and an experienced test pilot. See the CAA Safety Sense leaflet on performance.
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You have probably already read this, but it warrants taking seriously if you are thinking about short strips.
http://www.ais.org.uk/aes/pubs/aip/pdf/aic/4P036.PDF
Beyond that, several flying schools offer farm strip courses (e.g. Clacton aero club) as do some PFA coaches.
http://www.ais.org.uk/aes/pubs/aip/pdf/aic/4P036.PDF
Beyond that, several flying schools offer farm strip courses (e.g. Clacton aero club) as do some PFA coaches.
Why do it if it's not fun?
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To add to the good advice so far: Know your aircraft. Is its short-field performance limited by take-off or landing?
Most spam-cans can land in very short distances, but need more runway to take off from. This is generally a safe situation, since it's generally possible to take off in the specified distance (once all the safety factors have been added) regardless of your experience. In which case, all the advice from others on the thread is absolutely correct.
If you happen to be flying an aircraft which needs more runway for landing than it does for take-off, though, then lots of practice at a field with a bit of extra length is required first. You must be certain of being able to approach to exactly the point you want, at exactly the speed you need. Then measure the distance it takes you to stop on that runway (ideally in still wind, and at the same weight that you're planning on going to your short field), and add a safety factor to that to find your personal landing distances, which will improve as you practice.
Most spam-cans can land in very short distances, but need more runway to take off from. This is generally a safe situation, since it's generally possible to take off in the specified distance (once all the safety factors have been added) regardless of your experience. In which case, all the advice from others on the thread is absolutely correct.
If you happen to be flying an aircraft which needs more runway for landing than it does for take-off, though, then lots of practice at a field with a bit of extra length is required first. You must be certain of being able to approach to exactly the point you want, at exactly the speed you need. Then measure the distance it takes you to stop on that runway (ideally in still wind, and at the same weight that you're planning on going to your short field), and add a safety factor to that to find your personal landing distances, which will improve as you practice.
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One of the major problems when teaching short field techniques is the reluctance to feel what the aircaft is doing rather than relying on what the airspeed indicator is showing.
Make sure you know how your machine feels at low speed and forget all the "add 5kts for the wife and kids b*ll*cks" that most pilots seem to think is acceptable. With short strips you'll come a cropper very quickly with that sort of mentality.
As others have already pointed out, make sure you are aware of how much runway you will actually require and don't try to start with a very short field, but work your way down in size.
There aren't really any "tricks" as such for making short strip flying safer. If you are over loaded or don't treat the strip with respect, then there is no one trick that will keep you in one piece.
Use your common sense and practise, try setting limits on the runway you normally use, for instance touching down at a certain point and making sure you are stopped by another.
Eventually you'll be amazed at how little runway you actually need compared to others not flying "correctly."
Farm strip flying is also great fun and opens up a whole new realm of interesting places to go.
Just don't try short strips in something like a TB10 or Cherokee 140!
Make sure you know how your machine feels at low speed and forget all the "add 5kts for the wife and kids b*ll*cks" that most pilots seem to think is acceptable. With short strips you'll come a cropper very quickly with that sort of mentality.
As others have already pointed out, make sure you are aware of how much runway you will actually require and don't try to start with a very short field, but work your way down in size.
There aren't really any "tricks" as such for making short strip flying safer. If you are over loaded or don't treat the strip with respect, then there is no one trick that will keep you in one piece.
Use your common sense and practise, try setting limits on the runway you normally use, for instance touching down at a certain point and making sure you are stopped by another.
Eventually you'll be amazed at how little runway you actually need compared to others not flying "correctly."
Farm strip flying is also great fun and opens up a whole new realm of interesting places to go.
Just don't try short strips in something like a TB10 or Cherokee 140!
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Fly the correct speeds! These will almost certainly be lower than you think they ought to be.
Target threshold speed Vat = 1.3 x Vso i.e. 1.3 times stalling speed in approach config
If you're not sure about the aircraft's stalling speed at a particular weight you can always stall it at that weight - with an instructor if need be - then you have a reference point for calculating Vat
Then if the resulting figures are lower than you're used to flying the aircraft at, have a practice - again, with an instructor if need be - at flying the aircraft around at that speed to get the feel for it. That should make you feel comfortable that the 1.3 margin keeps the aircraft nicely in a controllable regime.
Same applies on take-off - if the flight manual best takeoff performance says rotate at X knots and climb at Y, then that's what you should do - adjusted for weight of course.
NS
Target threshold speed Vat = 1.3 x Vso i.e. 1.3 times stalling speed in approach config
If you're not sure about the aircraft's stalling speed at a particular weight you can always stall it at that weight - with an instructor if need be - then you have a reference point for calculating Vat
Then if the resulting figures are lower than you're used to flying the aircraft at, have a practice - again, with an instructor if need be - at flying the aircraft around at that speed to get the feel for it. That should make you feel comfortable that the 1.3 margin keeps the aircraft nicely in a controllable regime.
Same applies on take-off - if the flight manual best takeoff performance says rotate at X knots and climb at Y, then that's what you should do - adjusted for weight of course.
NS
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My best "short-field" advice is pretty obvious and I offer it to all who fly into my strip:
If you put your wheels down on the threshold, you will be unfazed!
Even with good clear approaches this requires the flare to happen before the a/c is over the strip.
Any tailwind component can really spoil your day up so do watch what the windsock is telling you.
Stik
If you put your wheels down on the threshold, you will be unfazed!
Even with good clear approaches this requires the flare to happen before the a/c is over the strip.
Any tailwind component can really spoil your day up so do watch what the windsock is telling you.
Stik
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stiknruda's advice about the flare is particularly worth noting. You can waste most of a 500m strip on a warm and windless day with a speed that is only slightly too high.
There is no magic to strip flying. It is just very different and far less forgiving than 1000's of feet of tarmac. It is very rewarding indeed but just don't get complacent and treat every strip with respect however long, wide or smooth you have been told it is.
Good luck.
There is no magic to strip flying. It is just very different and far less forgiving than 1000's of feet of tarmac. It is very rewarding indeed but just don't get complacent and treat every strip with respect however long, wide or smooth you have been told it is.
Good luck.
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Ditto everyone else: nail the speed on the approach and make sure it isn't too fast. Wind is critical, too, obviously. Going into somewhere really short I find the GPS groundspeed readout a real help. It gives that little bit of extra reassurance that it's all going to be OK.
QDM
QDM
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One tip I seem to remember being told was that if you haven't reached at least ½ your flying speed by the time you are a third the way down the runway on take off you won't make it, but you should still have time to stop.....
Spoon PPRuNerist & Mad Inistrator
It's true of any approach and landing, but perhaps more so in tighter situations - if you don't like the approach, GO AROUND! Don't try to make an arrival out of a poor approach, have another go.
The big advantage over a glider is that you have got an engine up front that (normally) allows you the luxury of another try (or two)!
Also, if you have made a couple of approaches and still aren't happy - reject the idea of landing! This supposes that you have enough fuel to get back home or to your alternate - so planning for a tricky approach should take this into consideration.
On short field take-offs, my instructors were very keen on not wasting an inch of runway when entering and lining up. Also, be fully conversant with the correct flap settings for the particular aircraft type and model you are flying. Just because one Cherokee / Warrior / Archer uses 2 stages of flap doesn't mean they all do - or that it is true in a Mooney etc.
The big advantage over a glider is that you have got an engine up front that (normally) allows you the luxury of another try (or two)!
Also, if you have made a couple of approaches and still aren't happy - reject the idea of landing! This supposes that you have enough fuel to get back home or to your alternate - so planning for a tricky approach should take this into consideration.
On short field take-offs, my instructors were very keen on not wasting an inch of runway when entering and lining up. Also, be fully conversant with the correct flap settings for the particular aircraft type and model you are flying. Just because one Cherokee / Warrior / Archer uses 2 stages of flap doesn't mean they all do - or that it is true in a Mooney etc.
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I'm only a low hour PPL with not a lot of experience outside of long, wide, paved runways.
Many years ago a pilot I knew quite well wanted to go to a grass strip up north. Having only long tarmac experience it daunted him so he wisely took along an instructor for the first trip and again for the second. Go a few months down the line and he'd established a reasonably frequent routine to this airfield.
One glorious June morning he set off again for B***** and rather grandly stuffed the aircraft through the hedge at the end of the runway. Not a mild prang either - wing ripped off (no fire luckily) and some very shaken passengers.
It didn't take long to see where things had started to go wrong. He'd flown there enough to become complacent and didn't see the odds stacking against him. All his earlier flights had been solo but, on this summer trip, he loaded the dice just a little too much:
1. Temperatures were around +21.
2. There wasn't a breath of wind.
3. He had four people on board and a lot of fuel - probably Max AUW minus the 40min fuel for the trip flown.
4. He'd been there enough to think it was no problem.
The scenario was all too obvious to him in hindsight - as it is to most readers here - but he never flew again.
A flight into a short grass strip has to be thought about carefully - not just the first flight but for every subsequent flight. Conditions change enough to make short strips definite go or no go candidates and it is up to the pilot to do the groundwork for every flight to see if they are in his favour.
Never, ever, get complacent on grass.. Keep your head sharp and they can be a lot of fun..
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One good rule of thumb is that you must attain 75% of take of speed by 50% of the TO run. If not abort, unless you really really know what you are doing!
Also, better to hold down in ground effect to build speed than to climb out with low airspeed.
And most of all, if all goes tits up, fly a controlled crash landing (if there is such a thing), and don't just stall into crash with nothing but the hope of a lucky outcome!!
SS
Also, better to hold down in ground effect to build speed than to climb out with low airspeed.
And most of all, if all goes tits up, fly a controlled crash landing (if there is such a thing), and don't just stall into crash with nothing but the hope of a lucky outcome!!
SS
Watching the video clip mentioned by ronnie3585 reminded me of a lesson I learned about taking off from narrow short strips. If you start to lose directional control either because of crosswind or improper use of rudder, there is a strong temptation to rotate before you attain the proper speed. Most of the spamcans I have flown will lift of at speeds about 5k below the ideal speed and you are then stuck in a high drag profile and you cannot gain enough height/speed to lower the nose.
Reading AAIB bulletins suggests to me that this is a relatively common cause of take off accidents. In my view, if you start to go sideways before you reach proper flying speed, abort the take off.
Reading AAIB bulletins suggests to me that this is a relatively common cause of take off accidents. In my view, if you start to go sideways before you reach proper flying speed, abort the take off.
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There are grass strips and grass strips. Barton for example might be grass, but you really do need to listen to the tower and lining up to wait is often the norm.
Off a farm strip, I see it as one continuous movement, keeping momemtum going when at the threshold, never stopping and running the risk of getting stuck. As has been suggested elsewhere, have a marker on the r/w which indicates the half way point. Know when to abort.
Equally, I do not deploy flap until desired speed has been reached (reduces drag in the roll). Once deployed, get it up sharpish and into the ground effect (for the low wing in particular), once required speed achieved for flight, up you go - for real.
On landing, you must nail the speed early. Always easier to add on a few knots.
Cardinal rule, use an instructor for the first few times.
The Wombat
Off a farm strip, I see it as one continuous movement, keeping momemtum going when at the threshold, never stopping and running the risk of getting stuck. As has been suggested elsewhere, have a marker on the r/w which indicates the half way point. Know when to abort.
Equally, I do not deploy flap until desired speed has been reached (reduces drag in the roll). Once deployed, get it up sharpish and into the ground effect (for the low wing in particular), once required speed achieved for flight, up you go - for real.
On landing, you must nail the speed early. Always easier to add on a few knots.
Cardinal rule, use an instructor for the first few times.
The Wombat
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Another thing's weight. Critical not only on the take-off obviously, but landing too. It puts your stall speed up and can leave you wallowing at speeds where usually you are nicely in control and the plane feels good. Read Stick and Rudder for a nice round-up of low speed handling (and everything else too).
Your aircraft light and your aircraft heavy are two completely different machines, confused at your peril.
Cheers,
QDM
Your aircraft light and your aircraft heavy are two completely different machines, confused at your peril.
Cheers,
QDM
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Great advice guys, keep it coming. Hopfully it will keep some of us out of the accident report pages
On the point of when it is best to rotate I have heard many differing views. The 172 I fly has will usually want to get airborne at about 55kts (on average of course) however in a shortfield situation i would prefer to keep it on the ground for another 10ks give or take - until it feels right. I dont rotate early as Im not fond of flying in the back end of the drag curve.
[B]Wombat[B] suggested to lift off and fly in the ground effect to bulid up speed. Would it not be safer to leave the main wheels on the ground (provided you have the runway distance) in case of crosswind, gusts, aborting the take off etc, instead of wallowing around in the ground effect in a low speed/high drag situation?
I know there are many variables e.g. wind, weight, temp & pressure etc but is there one "safer" method for take offs?
On the point of when it is best to rotate I have heard many differing views. The 172 I fly has will usually want to get airborne at about 55kts (on average of course) however in a shortfield situation i would prefer to keep it on the ground for another 10ks give or take - until it feels right. I dont rotate early as Im not fond of flying in the back end of the drag curve.
Originally Posted by wombat13
Once deployed, get it up sharpish and into the ground effect (for the low wing in particular), once required speed achieved for flight, up you go - for real.
I know there are many variables e.g. wind, weight, temp & pressure etc but is there one "safer" method for take offs?
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Originally Posted by ronnie3585
The 172 I fly has will usually want to get airborne at about 55kts (on average of course) however in a shortfield situation i would prefer to keep it on the ground for another 10ks give or take - until it feels right
NS